Yukon Government

Two caribou bulls clash during mating season.

The Porcupine Caribou Herd is one of the largest herds of mammals in North America. Currently numbering over 123,000 animals, the herd can appear to observers as a massive moving river of caribou passing over the landscape. Taking no notice of the international border between Canada and the U.S., each year the herd completes an arduous journey from the Yukon into Alaska. The known range of the herd is about 260,000 square kilometres.

The Porcupine Caribou Herd is a barren-ground caribou herd. This means the herd travels to different habitats within their range on a seasonal basis. Even very young calves travel with the herd, crossing open tundra, hills and mountain passes, and swimming swift-flowing rivers and streams. River crossings are particularly treacherous, especially during spring break-up when ice chokes the streams.